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7th Grade Math / Lesson 2: Order of Operations

ORDER OF OPERATIONS
What will we be learning in this lesson?


  • This lesson will review the order of operations with variable expressions.


ORDER OF OPERATIONS
 


Parenthesis   ( ),  [ ],  { }
Exponents
Multiplication/Division    from left to right
Addition/Subtraction       from left to right

 

Which of the operations would be done first in each expression?
 

  A.  20 - 4 * 5 + 1

   B.  32   - 7

   C.  (8-2)/3  + 5


ORDER OF OPERATIONS
 


Parenthesis   ( ),  [ ],  { }
Exponents
Multiplication/Division    from left to right
Addition/Subtraction       from left to right

 

Which of the operations would be done first in each expression?
 
A.  20 - 4 * 5 + 1              Do the multiplication first
 
B.  32     - 7                        Do the exponent first
 
C.  (8-2)/3   + 5                 Do the subtraction in the numerator first
 

 


ORDER OF OPERATIONS
 


  • State the operation that is performed first
  • Evaluate the expression (evaluate means "get an answer")
  1. 1.4 - 1 * 2 + 5                  
     
  2. 2.6 * 3 - 1 + 9
     
  3. 3.5 - 2 + 7 
 

 


ORDER OF OPERATIONS
 
  • State the operation that is performed first
  • Evaluate the expression (evaluate means "get an answer")
     
  1. 4 - 1 * 2 + 5                      Multiplication first.      7
  2. 2.6 * 3 - 1 + 9                      Multiplication first.      26
  3. 3.5 - 2 + 7                           Subtraction first.        10
 


ORDER OF OPERATIONS
 
  • Evaluate the expressions using the following values.
  • A = 4   B = 3   and   C = 2
  1.  4 - C * 2 + 5
  2. 2.A * B - 1 + 9
  3. 3.5 - 2 + B
 


ORDER OF OPERATIONS
 
  • Evaluate the expressions using the following values.
  • A = 4   B = 3   and   C = 2
  1.  4 - C * 2 + 5         4 - 2 * 2 + 5    =    4 - 4 + 5 =     0 + 5 =   5
  2. 2.A * B - 1 + 9          4 * 3 - 1 + 9   =    12 - 1 + 9    =   11 + 9    =   20
  3. 3.5 - 2 + B                5 - 2 + 3   =   3 + 3   =    6
 


ORDER OF OPERATIONS
 
  • Put parenthesis into the following statement to make it true.
     
  1.      5 + 2 * 3 - 1 =  9
 
 


ORDER OF OPERATIONS
 
  • Put parenthesis into the following statement to make it true.
     
  1.      5 + 2 * 3 - 1 =  9
  • You need to just try putting parenthesis into different spots in the statement until you find the one that works.
  • (5 + 2) * 3 - 1
  • 7 * 3 - 1
  • 21 - 1
  • 20                Not this one.
 
 


ORDER OF OPERATIONS
 
  • Put parenthesis into the following statement to make it true.
     
  1.      5 + 2 * 3 - 1 =  9
  • Try a different spot.
  • 5 + (2 * 3) - 1
  •      5 + 6 - 1
  •       11 - 1
  •            10                Not this one.
 
 
 


ORDER OF OPERATIONS
 
  • Put parenthesis into the following statement to make it true.
  1. 1.5 + 2 * 3 - 1 =  9
  • Try a different spot.
  • 5 + 2 * (3 - 1)
  •      5 + 2 * 2
  •       5 + 4
  •           9                This one.
                                 5 + 2 * (3 - 1) = 9   is the true statement.
 


 
  • Can you evaluate an expression according to the order of operations?

  • Be sure to go back to the lesson page to access your homework.